There have been various attempts to develop non-polyvinyl chloride (non-PVC) floorings. However, since non-PVC floorings suffer from many problems, such as difficult production, poor installation and high price, they are not yet suitable for practical use. In recent years, floorings using polyolefin resins have been developed and introduced into the market in Japan.
However, polyolefin resins, including polypropylene and polyethylene, have no adhesion to inks, surface treatment agents and other components due to the absence of polar components in the resins. Accordingly, production of polyolefin floorings essentially involves various complicated processes, such as corona treatment and primer treatment, for sufficient adhesion to inks and surface treatment agents. Further, viscosity characteristics of polyolefin resins are drastically deteriorated during melting above specific temperatures, and thus polyolefin resins cannot be substantially molded into sheets by calendering. Accordingly, the use of an extruder, e.g., a T-die, is inevitable, leading to a serious deterioration in productivity.
Although processing of polypropylene and ethylene-propylene rubbers has been recently performed by calendering, the problem of poor adhesion to inks and surface treatment agents still remains unsolved.